Thanks for the revision to your post Scott. I of course was being flip about 'anything you want it to be', but in fact I have heard it argued that way in reference to 'Proper Course" The old 'mast abeam may have been lacking in clarity on the course, but it had at least a recognizable and identifiable criteria.
This rule leaves it up to the protest committee and both skippers ability to press an argument and win. It would require graphic submission I am sure. I wish it were clearer. But it is not and even the real ACC has problems. That of course is match racing. Do the same thing in a fleet race and the overtaking boat will likely lose a place trying to get thrugh the wind shadow of the windward boat. There are tactical alternatives for the overtaken boat, assuming there is some wind to work with, and forewarned is forearmed.

This is an example of how confused things can become. Just attended the Elon regatta which was a 4 mark course. I am half way between mark 3 and mark 4 (the downwind end of the course) when a yacht begins to pass me to windward. We are not in the zone. He starts to "crowd" me and I yell for "windward boat boat keep off of me". He responds "I AM SAILING MY PROPER COURSE" and persists on cutting in. (I yielded, and did not protest).

I don't know who the other competitor was, but he must have come up with that "I am sailing my proper course" line by reading (misreading) this thread. He said it with such sincerity that I let him in! Oh, well.

Yachtie is absolutely correct. This chain was about a Leeward boat having to sail its proper course when it is limited by Rule 17.1. There is NO proper course for a windward boat. Especially one trying to pass you. You should have taken him head-to-wind and then discussed his proper course on the beach. [}:)][:p]

Ah, poor Joe and his Charleston escapades. Ricky is agressive but he knows the rules. Part of winning is knowing the rules and using them.

"Head to wind." I lurk behind a pair that are match racing the fleet and slip quietly by when they get territorial. Momentum is everything.

You are such a gentleman Winston on this difficult short leg. I like the response, "Clear my windward rail, Sir, or find yourself to the rear of the fleet." A 360 at Elon is desvastating and a trip to B fleet. I don't think I will use "Come Up" anymore...it seems so offensive.

Gee guys, I hate to get into this discussion at such a late date; but let me see if I can reduce the discussion to the issue to a manageable one.

First; RRS 17.1 applies only in a condition where the leward boat overtakes a windward one. Second, the only proper course is the one determined by the ROW boat. The give way (windward) can either accept that position or ask the protest committee to determine if the ROW was sailing too high. The facts found will overide any pond side negotiations.

RRS 18 trumps RRS 17. The passage of 2 overlapped boats of a group of slower boats (obstructions) and "inside the circle" conditions are governed by RRS 18. so you can sail as high as you need to to make a proper pass or "seaman like" mark rounding.

Actually the rule is simple once the facts are determined and the non relavent things (mast abeam) and emotions are dismissed from the discussions. Probably the best way to learn these things is to "take it to committee" and not argue it out on the pond.

To ice the cake further; please remember that you do not have to hit the other guy to prove your point. (RRS 14)

If you know the rules you can be confident of prevailing. Knowing the rules also means knowing the appeals case book. If you just <i><b><i>think</i></b></i> you know the rules (or rely on your memory of years gone by) you are probably in for a surprise. Someone who just bellows out in a loud voice to intimidate a competitor deserves a trip to the committee.

After looking at the many comments and links offered, case book, other discussion sites, etc. I think I understand how a 17.1 situation will be ruled by protest committee. Two boat length and duration of the overlap clauses appear to be superfluous. Never addressed.

I'll stick with my feeling that 17.1 is the Seinfeld rule.
L can 'go where you wanna go, do what you wanna do' as the old song says. Lousy rule, common conflict. Let the committee rule.

Thanks for the link Peter- lurked and read them over. Seems the subjective definition of proper course rises again.
Found a sailing instructions page from a 1970's ACCR diagraming how 'mast abeam' would be intrepreted on our boats (skippers position being hard to apply) At least it was difinable and a diagram possible, not so for 'proper course'. I look forward to next issue of Model Yachting to stimulate further discussion, amd a protest meeting.